Police in Germany are searching for a Tunisian man, who is believed to have been at the wheel of the truck that rammed into a crowd at a Christmas market in Berlin and killed a dozen people.
Local media reported on Wednesday that a manhunt had begun in the wake of the deadly attack that also injured nearly 50 people.
Asylum papers were discovered in the truck.
The federal prosecutors' office of Germany has named the prime suspect as Tunisian national Anis Amri.
The office said the 24-year-old suspect "could be violent and armed." A reward of 100,000 euros ($104,000) has also been offered for information leading to the arrest of Amri.
German Interior Minister Thomas de Maiziere earlier said in a press conference, "There is a new suspect we are searching for, he is a suspect but not necessarily the assailant."
Stephan Meyer, a lawmaker with Germany's governing conservatives, told reporters at the same conference that the “dangerous” suspect was Tunisian and was known to authorities. "We are apparently talking about a potentially dangerous suspect who was known to authorities."
On Tuesday, German police released a Pakistani national, who had been arrested near the market in connection with an investigation into the attack. The man, police sources said, matched witness descriptions of the truck's driver but there was no evidence that could link him to the deadly ramming.
German authorities said they had received over 500 tips on the attack as of Tuesday night. Prosecutors, however, declined to comment that whether they had any concrete leads or any indication that they were looking for more than one suspect.
"We don't know for sure whether it was one or several perpetrators," said German Prosecutor Peter Frank. "We don't know for sure whether he, or they, had support."
The Daesh Takfiri terrorist group claimed responsibility for the attack in the German capital. It said the assault was a response to Germany's contribution to a so-called coalition led by the United States that purportedly fights Daesh in Iraq and Syria.
The Takfiri terrorist group also claimed a similar attack in France's southern city of Nice in July, when a truck plowed into a crowd celebrating Bastille Day. More than 80 people were killed in the attack.
